Boodlea

Abstract: Nucleotide sequences from the nuclear rDNA internal transcribed spacers (ITS1 and ITS2) and seven morphological characters were compared among 10 isolates of siphoncladalean algae representing six species in Boodlea, Chamaedoris, Cladophoropsis and Struvea. Parsimony analysis of both datasets revealed that Struvea is not monophyletic, Struvea elegans Borgesen being more closely related to Chamaedoris peniculum (Ellis et Solander) Kuntze and Struvea anastomosans (Harvey) Piccone et Grunow being more closely related to Cladophoropsis membranacea (Hofman Bang ex C. Agardh) Borgesen. Parsimony analysis of the ITS data further indicates that Cladophoropsis is not monophyletic and that Cladophoropsis and Boodlea may be paraphyletic. The influences of life history strategies, overlapping gene pools and the possibility of introgression are discussed. Finally, the point is made that although the results help to clarify phylogenetic relationships among species within these genera, they also illustrate the hazard of a priori assumptions about generic monophyly in which a single species (often the most commonly recognized one) is used to represent that genus in a biogeographic and/or phylogenetic study.

Abstract: The marine benthic green macroalgae of the New South Wales mainland and of Lord Howe Island are listed, each with bibliographic, distributional and specimen-voucher details. Included are 113 species in 9 orders, 14 families and 38 genera, of which 12 species are based on New South Wales types. With respect to biodiversity, New South Wales is as rich in numbers of genera and species as southern Australia. Eight genera (Pedobesia, Boodlea, Neomeris, Trichosolen, Ventvicaria, Caulerpella, Pseudochlorodesmis, Sporocladopsis) and 41 species are new records for the State, and 14 species are newly recorded for the Australian continent. The largest genus represented is Cladophora; 22 species are recorded, 13 from Lord Howe Island alone, and 7 are new to Australia (C. cymopoliae, C. colabense, C. dotyana, C. nigrescens, C. ohkuboana, C. patentirainea, C. ryukyuensis). Examination of type and recently collected material of Caulerpa annulata (from Port Arthur, Tasmania) shows it to be synonymous with the earlier Caulerpa hodgkinsoniae (from Ballina, New South Wales).

Abstract: Microfibril arrangement patterns and the relationship between microfibril and cortical microtubule arrangement were investigated in growing thallus cells in the coenocytic green alga, Boodlea coacta. The thallus exhibited tip growth with a slight spiral. Microfibril layers in the walls showed three characteristic fibril orientations: longitudinal, oblique, and transverse to the cell axis. The fibrils in each layer formed from the cell apex to the base. Cortical microtubules in the peripheral cytoplasm were always longitudinal. Newly formed, longitudinally oriented microfibrils were parallel to the cortical microtubules, but oblique and transversely oriented microfibrils never were. This is an indication that microfibril orientation in Boodlea cell walls is not necessarily related to cortical microtubule arrangement.

Abstract: Boodlea composita (Harvey) F. Brand and Phyllodictyon anastomosans (Harvey) Kraft & M.J. Wynne, two widespread tropical siphonocladalean green algae, have had a long and confusing history because of the vague taxonomic boundaries between the two species. Molecular phylogenetic studies on the basis of nuclear-encoded rDNA sequences have resolved these indistinct species boundaries and suggest these taxa are part of a species complex. Detailed morphological investigations in combination with field and culture observations show that the concept of traditionally recognised taxa in this species complex is clouded by an ecologically induced phenotypic plasticity and developmental variability. Examination of a large number of specimens of B. composita, P. anastomosans and morphologically allied taxa including Boodlea siamensis Reinbold, Boodlea montagnei (Harvey ex J.E. Gray) Egerod, Nereodictyon imitans Gerloff and Struveopsis siamensis (Egerod) P. C. Silva, worldwide, including types, shows a wide morphological variety. We recognise seven more or less distinct morphological entities based on differences in thallus architectures, branching systems, cell dimensions and tenacular cell types. Awaiting the recovery of the true nature of the defined entities in this species complex (different species or growth forms of the same species), they are referred to as morphotypes, i.e. making no assumptions as to which taxonomic level they best apply.